The present invention generally relates to a system and method for testing a laser module by measuring its side mode suppression ratio.
A key requirement of a fiber optic communication system is its ability to transmit data from one location to another relatively free of errors in the data stream. The data stream error rate is a function of the error rate of the laser module utilized to transmit the data. For fiber optic communication systems where the goal is to transmit data over long distances at high bit rates, the typical acceptable error rate is on the order of one error in one trillion bits (or 1xc3x9710xe2x88x9212). In the future, even lower error rates may be required.
The prior art has provided a method for measuring the actual error rate of a laser module by utilizing a bit error rate tester to compare data transmitted through the laser module with its output over a length of time. This method is time-consuming and requires dedication of expensive capital equipment for a long period of time for each laser module tested. In addition, the method must be repeated at several different temperatures in order to simulate actual use conditions. The testing process causes wear and tear to the laser module, which has a finite useful life.
Accordingly, there remains a need in the art for a rapid, efficient and easily-automated method for testing a laser module in order to determine whether its bit error rate falls within acceptable limits for the intended application of the laser module, and a system capable of performing this method.
The present invention addresses, inter alia, the foregoing needs by providing a relatively fast and efficient method of testing a laser module by measuring a first side mode suppression ratio of the laser module output while operating the laser module at a first bias setting, measuring a second side mode suppression ratio of the laser module output while operating the laser module at a second bias setting, and generating a test result for the laser module in accordance with the difference between the first and second side mode suppression ratio measurements. The present invention further provides a system for performing the method of the invention.